(2) Arthropoda Flashcards
“Joint-legged”
horseshoe crabs, spiders, scorpions, ticks, mites, crustaceans, millipedes, centipedes, insects
Largest Phylum=
900,000 described species
- 75% of all species on earth
-Widest, densest distribution on earth
*2-30 million species
Chitinous Exoskeleton (Arthropoda Characteristics)
a. protective, lightweight, water-conserving
b. doesn’t grow, must be molted periodically
Molt
ecdysis
Tagma (Arthropoda Characteristics)
a body unit made up of multiple fused body segments
Respiration (Arthropoda Characteristics)
cutaneous if small and aquatic; or gills, tracheae, book lungs, book gills
*not true gills
Arthropoda Characteristics
- joint appendages
- exoskeleton
- Metamerism
- Tagma
- Respiration
- open circulation
- complete digestive system
Subphylum Chelicerata Characteristics
a. 6 pairs of appendages (12)
-4 pairs of walking legs (except crabs)
-1 pair of pedipalps (food handlers)
-1 pair chelicerae (pointed mouthparts)
b. fused head/thorax
c. no antennae or mandibles
Class Merostomata
Horshoe crab
a. 5 pairs of walking legs, 1 pair of chelicerae
b. marine
c. feed nocturnally
d. lays egg on beaches in spring
e. blood for vaccine testing
Order Aranae (Class Arachnida)
- Chelicerae = fangs, inject venom
- Pedipals manipulate food; male uses it to transfer spermatophore to the female
- Eight simple eyes
- silk glands
- Control insects
Order Scorpiones (Class Arachnida)
- Pedipalds= claws/ pinchers
- Stinger with venom at end of tail
- secretive, nocturnal
- mother carries young on back
Black Widow Toxin
Neurotoxin, attacks nervous system
Brown Recluse Toxin
Hemotoxin, attacks blood tissue
Order Opiliones (Class Arachnida)
daddy long legs
1. Cephalothorax and abdomen nearly fused
2. lose leg as defense, but not regenerated
3. scavenging or predatory
Order Acari (Class Arachnida)
ticks
1. Cephalothorax and abdomen completely fused
2. Nutrition
-free-living
-ectoparasites (Lyme disease, rocky mountain)
Ex: chogger= itching
Characteristics (Subphylum Myriapoda)
- Many footed
- One pair of antennae
Class Chilopoda (Subphylum Myriapoda)
*centipedes
1. One pair of legs per segment
2. one pair of anterior poison claws
3. carnivorous
4. Agile, nocturnal, prefer moisture
Class Diplomoda (Subphylum Myriapoda)
*milipedes
1. Two pair of legs per segment
2.herbivorous
3. Slow, coil for protection
Characteristic (Subphylum Crustacea)
- Principally aquatic
- Most have a shell = cuticle secreted with high calcium content
- two pairs of antennae
- appendages biramous (forked) unless modified
- head, thorax, cephalothorax, abdomen (all are tagma)
- Excretory system: antennal or maxillary glands at base of these appendages
Reproduction (Subphylum Crustacea)
- Most dioecious; barnacles monoecious
- Development
- direct = no larva
-indirect = larva or nymph
Class Maxillopoda (Subphylum Crustacea)
- Copepods
- freshwater and marine
-primary component of plankton
- intermediate hosts to some human parasites - barnacles
- marine
-adult with shell
-filter feeds using legs
-reduce ships speed 30-40%
Order Isopoda (Class Malacostraca)
-many small marine and freshwater
-terrestrial pillbugs/woodlice - internal gills
Order Euphausiacea (Class Malacostraca)
Krill
-primary food for baleen whales, many fish
Order Decapoda (Class Malacostraca)
crayfish, lobsters, crabs
- five pairs of walking legs
- small swimming larva for most
Characteristics (Subphylum Hexapoda)
- primarily terrestrial
- one pair of antennae
- Six appendages
- Malpighian tubules - excretion
Class Insecta (Subphylum Hexapoda)
- More species (+1 million) than any other classes
- widespread except marine
- three pairs of legs, one pair of antennae
- flight - wings are outgrowths of thorax wall
- Nutrition
